Device for lateral movement of sheets

ABSTRACT

The present invention relates to a device for lateral movement of sheets ( 2 ) during transport thereof to a stacking device ( 11 ) such that the sheets ( 2 ) or stacks of sheets occupy laterally displaced positions relative to each other in the stacking device ( 11 ). A high-speed printer ( 6 ) is provided for printing the sheets ( 2 ) or a continuous web which is then cut to sheets ( 2 ). A vacuum generating device has vacuum means ( 12, 13 ) with vacuum openings located within vacuum holes ( 20 ) in conveyor belts ( 14 ), and is provided to generate a vacuum in said vacuum openings and vacuum holes ( 20 ) so that said conveyor belts ( 14 ) can grip or engage and transport the sheets ( 2 ). A vacuum control device is provided to control the vacuum generating device to alternatingly either generate a vacuum in at least one vacuum opening in one of the vacuum means ( 12 ) or in at least one vacuum opening in the other vacuum means ( 13 ) such that one or more sheets ( 2 ) are engaged and transported of fed by one or the other conveyor belt ( 14 ) of said vacuum means ( 12, 13 ).

[0001] The present invention relates to a device for lateral movement ofsheets during transport thereof to a stacking device such that thesheets occupy laterally displaced positions relative to each other inthe stacking device.

[0002] A high-speed printer is provided for printing sheets or acontinuous web which is then cut to sheets.

[0003] The device comprises at least one pair of conveyor belts whichare diverging relative to a main transport direction such that they canmove sheets laterally in different directions relative to said maintransport direction.

[0004] A gripping and contact maintaining appliance is provided suchthat the conveyor belts can grip or engage sheets and hold them incontact with said conveyor belts for transport thereby.

[0005] Devices for lateral movement of sheets or piles of sheets duringtransport thereof to a stacking device, are previously known from U.S.Pat. No. 5,540,370. At these prior art devices, conveyor belts are usedfor lateral movement of the sheets relative to each other. For shiftingthe sheets between different conveyor belts and keep the sheets incontact therewith, balls affected by magnetic forces are used. Suchdevices however, are not suitable when it comes to transport webs ofsheets or individual sheets at high speeds, e.g. 2 m/s, throughhigh-speed printers, e.g. laser printers, for printing webs of sheets orindividual sheets.

[0006] In DE 198 19 736 devices with conveyor belts are described,utilizing a vacuum for gripping and transporting sheets. Said transportbelts are adapted to move together sheets from two stacks to a singlestack and not to provide different piles of sheets.

[0007] In U.S. Pat. No. 4,572,497 there are described devices withconveyor belts which utilize a vacuum for gripping and transportingsheets. The conveyor belts are adapted for lateral movement of thesheets and not to provide different piles of sheets.

[0008] U.S. Pat. No. 5,133,543 relates to devices at which sheets aretransported by conveyor belts and held in contact therewith by means ofa vacuum. These devices are not adapted for lateral movement of sheetsrelative to each other, but have diverging conveyor belts for stretchingthe sheets. The devices are not suitable for use in connection withhigh-speed printers requiring high feed speeds on the webs of sheets orthe individual sheets.

[0009] The object of the present invention has been to provide a devicewhich are capable of moving sheets laterally at such high speed that itis suitable for use in connection with high-speed printers. This isarrived at by providing the device according to the invention with thecharacterizing features of subsequent claim 1.

[0010] Since the device according to the invention utilizes a vacuum forlateral movement of the sheets, said sheets can be moved or displaced athigh speed. By further using a vacuum control device which controlsgeneration of a vacuum in one of the conveyor belts but not the otherand vice versa, it is guaranteed that sheets transported on one of theconveyor belts can not be affected by the other, which is particularlyimportant if the conveyor belts are lying close together.

[0011] The invention will be further described below with reference tothe accompanying drawings, in which

[0012]FIG. 1 is a schematic side view of a device according to theinvention, forming part of a plant for printing sheets in a high-speedprinter;

[0013]FIG. 2 is a schematic perspective view of a device according tothe invention and in a part of the plant of FIG. 1;

[0014]FIG. 3 is a schematic view of a device according to the inventionand in a part of the plant of FIG. 1;

[0015]FIG. 4 is a schematic side view of a device according to theinvention and in a part of the plant of FIG. 1;

[0016]FIG. 5 is a perspective view of a vacuum means forming part of theplant of FIG. 1;

[0017]FIG. 6 is a plan view of parts of the vacuum means of FIG. 5;

[0018]FIG. 7 is a side view of the vacuum means of FIG. 6;

[0019]FIG. 8 is a perspective view of another vacuum means forming partof the plant of FIG. 1;

[0020]FIG. 9 is a side view, partly in section, of a part of the vacuummeans of FIG. 8;

[0021]FIG. 10 is a plan view of an alternative lateral-movement deviceforming part of the device according to the invention; and

[0022] FIGS. 11-14 are schematic side views of parts of a stackingdevice forming part of the device according to the invention, wherebydifferent parts of the stacking device have different positions.

[0023] In FIG. 1 there is illustrated a plant 1 for printing sheets 2,said plant 1 comprising an unrolling stand 3 with a roll 4 of paper oranother suitable material which is fed as a continuously running web 5from said unrolling stand 3 into a high-speed printer 6, e.g. a laserprinter, for printing. With high-speed printer 6 is meant a printerwhich can print the running web 5 when said web passes the printer athigh speed, e.g. 2 m/s or even more. After printing the web 5 in thehigh-speed printer 6, it is brought to run to a cutting device 7 inwhich the web 5 is cut to sheets 2 by means of knives 8 which can berotatably mounted. From the cutting device 7, the sheets 2 are fedcontinuously to a transport device 9 which transports the sheets 2 to adevice 10 for lateral movement thereof in opposite lateral directions B,C relative to a main transport direction A (see FIG. 3). The lateralmovement of the sheets 2 in lateral directions B, C is carried throughfor locating the sheets or stacks 2A, 2B of sheets 2 in laterallydisplaced positions relative to each other in a stacking device 11 intowhich the sheets 2 are transported from the lateral-movement device 10.Generally, the laterally moved or displaced stacks 2A, 2B shall lie ontop of each other and there may be more than two such stacks 2A, 2Blying on top of each other.

[0024] The plant 1 may comprise a prior art device (not shown) forlocating two webs 5 on top of each other, which are brought to runthrough the high-speed printer 6 and cut in the cutting device 7 to twinsheets, which are transported by the transport device 9 to thelateral-movement device 10 in which the twin sheets are laterally movedor displaced. Then, the twin sheets are transferred to the stackingdevice 11, in which said twin sheets are stacked. Eventually, three orfour webs can be located on top of each other and treated in the sameway.

[0025] The lateral-movement device 10 includes a vacuum generatingdevice V having at least one pair of vacuum means 12, 13 or anothersuitable number of pairs of vacuum means, e.g. three pairs (see FIG. 3).At each vacuum means 12 and 13 there is provided an endless conveyorbelt 14 which runs about rolls 15, 16 at the opposite end portions ofthe vacuum means 12 and 13 respectively (see FIG. 5). The conveyor belts14 are driven or operated in a transport or feed direction by means of adriving device (not shown) and at a speed which is adapted to the speedof the web 5 and the sheets 2. The vacuum means 12, 13 and theirconveyor belts 14 are provided diverging somewhat relative to the maintransport direction A and the angle α therebetween may lie within arange of 4-8°, which means that the angle between said main transportdirection A and each lateral direction B, C is within a range of 2-4°.The angle α however, may lie within a wider range.

[0026] Each vacuum means 12, 13 has three vacuum openings 17, 18 and 19which are located in a row, in line, after each other seen in therespective lateral direction B and C. Another number of vacuum openingsthan three is also possible. The conveyor belt 14 has a number of vacuumholes 20 which are located in a row after each other in the longitudinaldirection of the conveyor belt 14 and these vacuum holes 20 pass overthe vacuum openings 17, 18, 19 of the respective vacuum means 12, 13when the conveyor belt 14 is moved relative to said vacuum means 12, 13.

[0027] Each vacuum means 12 and 13 respectively, has a channel system 21which through a compressed-air line 22 is connected to a compressed-airgenerating device 23. The channel system 21 is adapted to guidecompressed air to an ejector 24, i.e. a jet pump, in association witheach vacuum opening 17, 18, 19. The channel system 21 includes, for eachvacuum opening 17, 18, 19 a horizontal channel 25 to which a verticalchannel 26 is connected. The channel 26 transforms into a horizontalejector channel 27 which is directed beyond the lower end of a verticalhole 28 which at the top communicates with the respective vacuum opening17, 18, 19. The ejector channel 27 runs to a compressed-air outlet 29through which the compressed air flows out of the ejector 24.

[0028] When the ejector 24 is activated, compressed air is brought topass through the channels or passages 25, 26 into its ejector channel27. Since the speed of the jet D of compressed air (FIG. 7) in thisejector channel 27 is high, air will be sucked thereinto from eachvacuum opening 17, 18, 19 through the vertical hole 28, whereby a vacuumis generated, i.e. a negative pressure, in each vacuum opening 17, 18,19 and in the vacuum holes 20 communicating therewith, in the conveyorbelt 14.

[0029] A vacuum control device 30 is provided to see to that there iseither a vacuum in the respective vacuum opening 17, .18, 19 and thevacuum holes 20 in the conveyor belt 14 at said vacuum openings, or tointerrupt or withdraw said vacuum. The vacuum control device 30incorporates a vacuum interrupting or vacuum withdrawing device 31 ateach ejector 24 in order to feed compresses air from the compressed-airgenerating device 23 to the respective vacuum opening 17, 18, 19 forquick and effective withdrawal of the vacuum therein and in the vacuumholes 20 communicating therewith, in the conveyor belt 14. Each vacuuminterrupting or vacuum withdrawing device 31 includes a valve 32,preferably an electric valve, through which compressed air can pass froma passage branch 25 a of the horizontal channel 25 into a horizontalchannel 33 having its opening 34 at the top in the vertical hole 28.When the valve 32 is closed, the connection between the channels orpassages 25 a, 33 is closed too, and the compressed air flows throughthe vertical channel 26 to the ejector channel 27 with ejector effect inthe ejector 24 as a result, and thereby generation of a vacuum in therespective vacuum opening 17, 18, 19 and consequently in vacuum holes20, in the conveyor belt 14, communicating with the vacuum opening inquestion. If the valve 32 is opened, compressed air will flow throughthe channels 25 a, 33 to the vertical hole 28 and immediately interruptthe vacuum therein and thereby in the respective vacuum opening 17, 18,19 as well as in the vacuum holes 20 in the conveyor belt 14, whichcommunicate with the vacuum opening in question. Preferably, compressedair will in this case generate a certain additional or positive pressurein the vertical hole 28 and in the respective vacuum opening 17, 18, 19and thereby in the vacuum holes 20 communicating with the vacuum openingin question, in the conveyor belt 14. This is marked with an arrow E inFIG. 7.

[0030] The setting of the valves 32 in vacuum generating or vacuuminterrupting positions is controlled by means of a vacuum control unit35 which can be programmed to see to that a vacuum is present in avacuum opening 17, 18, 19 or not.

[0031] The vacuum control device 30 described above can be programmedsuch that the conveyor belts 14 of the vacuum means 12, 13 alternatinglygrip or engage and transport or feed one or more sheets 2 in thedifferent lateral directions B or C in order to, in the stacking device11, locate the sheets 2 or stacks 2A, 2B of sheets in laterallydisplaced positions relative to each other. If e.g. laterally displacedstacks 2A, 2B of sheets containing three sheets each shall be formed inthe stacking device 11, the vacuum control unit 35 is programmed forcontrol of the vacuum generating device V in the following way.Initially, a vacuum is generated in the vacuum openings 17, 18, 19 ofthe vacuum means 12 and thereby in the vacuum holes 20 in its conveyorbelt 14, but not in the vacuum openings 17, 18, 19 of the vacuum means13 and thereby neither in the vacuum holes 20 in its conveyor belt 14.When the first sheet 2 is transported or fed to the device 10 forlateral movement, the conveyor belt 14 of the vacuum means 12 will, dueto the vacuum in its vacuum holes 20, grip or engage and transport thissheet 2 in the lateral direction B. The following two sheets 2 will alsobe moved in the lateral direction B to form a stack 2A consisting ofthree sheets 2 in the stacking device 11. Then, a vacuum is generated inthe vacuum openings 17, 18, 19 of the vacuum means 13 instead, andthereby in the vacuum holes 20 in its conveyor belt 14, while the vacuumgeneration in the vacuum openings 17, 18, 19 of the vacuum means 12 andthereby in the vacuum holes 20 in its conveyor belt 14 is brought tocease or is interrupted. Hereby, the next sheet 2 fed to the device 10for lateral movement is engaged and transported by the conveyor belt 14of the vacuum means 13 in the lateral direction C, and so are thefollowing two sheets 2 such that a stack 2B consisting of three sheets 2and laterally moved relative to the stack 2A is formed in the stackingdevice 11. This alternating movement laterally is continued until arequired number of, relative to each other, laterally moved stacks 2A,2B have been formed in the stacking device 11.

[0032] The vacuum control device 30 can be programmed to bring thevacuum generating device V to generate as well as not to generate orinterrupt a vacuum in e.g. the following ways:

[0033] A) A vacuum is generated in the first vacuum opening 17 in thefirst vacuum means 12 and is generated at the same time or isinterrupted at the same time in at least one of the following vacuumopenings 18, 19 in said first vacuum means 12. A vacuum is not generatedor is interrupted at the same time in at least the first vacuum opening17 of the vacuum openings 17, 18, 19. in the second vacuum means 13.

[0034] B) A vacuum is generated in the first vacuum opening 17 in thesecond vacuum means 13 and it not generated at the same time or isinterrupted at the same time in at least one of the succeeding vacuumopenings 18, 19 in said second vacuum means 13. A vacuum is notgenerated at the same time or is interrupted at the same time in atleast the first vacuum opening 17 of the vacuum openings 17, 18, 19 ofthe first vacuum means 12.

[0035] C) A vacuum is generated in the first vacuum opening 17 in thesecond vacuum means 13 and in at least one of the succeeding vacuumopenings 18, 19 in said second vacuum means 13. A vacuum is notgenerated at the same time or is interrupted at the same time in thevacuum openings 17-19 in the first vacuum means 12.

[0036] D and E) A vacuum is generated in the first vacuum opening 17 inthe first vacuum means 12 and is not generated or is interrupted at thesame time in the first vacuum opening 17 in the second vacuum means 13while it at the same time is generated in any or both of the othervacuum openings 18, 19 in the second vacuum means 13 or vice versa.

[0037] F and G) A vacuum is generated in all vacuum openings 17, 18, 19in the first vacuum means 12 but is not generated at the same time or isinterrupted at the same time in all vacuum openings 17, 18, 19 in thesecond vacuum means 13 or vice versa.

[0038] The vacuum control device 30 can be programmed to bring thevacuum generating device V to generate respectively to not generate orinterrupt a vacuum in another order depending on the size of the sheets2 relative to the length of the conveyor belts 14 and/or the feed speedor in dependence of other circumstances.

[0039] The vacuum control device 30 can also control the vacuumgenerating device V such that a vacuum is generated in a vacuum opening17, 18 or 19 when front portions of a sheet 2 during transport by theconveyor belt 14 reach over this vacuum opening 17, 18 or 19 and suchthat the generation of vacuum is interrupted when said front portions ofthe sheet 2 leave their positions over said vacuum opening 17, 18 or 19.Furthermore, the vacuum control device 30 can control the vacuumgenerating device V such that a vacuum is interrupted or withdrawn insuch a vacuum opening 19 within the extension of which rear portions ofa sheet 2 are situated when front portions of the sheet 2 are brought toleave the conveyor belt 14 transporting said sheet 2, e.g. when saidsheet is turned over by the conveyor belt to the stacking device 11.These functions may alternatively be obtained by a particular shapeand/or location of the vacuum openings 17-19.

[0040] Two conveyor belts 14 may lie so close to each other that thesheets 2 can have such a size that they during transport on one of theconveyor belts 14, at least during a part of their transport along saidconveyor belt 14, move above the other conveyor belt 14. At such arelative location of the conveyor belts 14, it is important that thevacuum control device 30 controls the vacuum to be present only in thatconveyor belt 14 which transports the sheets, and that a vacuum is notpresent in the other conveyor belt 14. Hereby, it is ensured that thetransport of the sheets 2 with one conveyor belt 14 is not disturbed bya vacuum in the other conveyor belt 14.

[0041] The transport device 9 of the plant 1 includes several, e.g. sixconveyor belts 9 a located beside each other. These conveyor belts 9 aextend around vacuum means 9 b illustrated in FIG. 8. Each vacuum means9 b has a first vacuum opening 9 c and a second vacuum opening 9 d whichare elongated and located in a row after each other in the maintransport direction A of the sheets 2. The first vacuum opening 9 c hasclosed end portions 9 ca and 9 cb, while the second vacuum opening 9 dhas a front end portion 9 da, seen in the main transport direction A,which is closed, but an open rear end portion 9 db.

[0042] The vacuum means 9 b form part of a vacuum generating device VAwhich is adapted to generate a vacuum in the vacuum openings 9 c, 9 dand thereby in vacuum holes 9 e provided in the conveyor belts 9 a suchthat sheets 2 transported to the transport device 9, are engaged by theconveyor belts 9 a and maintained in contact therewith for transportthrough said transport device 9.

[0043] The illustrated embodiment of the vacuum generating device VAincludes a compressed-air generating device 9 f which cooperates with anejector 9 g at each vacuum opening 9 c, 9 d. The ejector 9 g can belocated in the vacuum means 12 and/or 13 which preferably is elongatedand about which the conveyor belt 9 a runs. Hereby, the ejector 9 g issituated close to the conveyor belt 9 a, which, inter alia, provides fora simple construction, since there is no need for long channels orpassages between the ejector 9 g and the conveyor belt 9 a. At theillustrated embodiment, the ejector 9 g is provided in a vacuum means 12and/or 13 in the form of an elongated rule including said rolls 15, 16around which the conveyor belt 9 a runs. Thus, the compressed-airgenerating device 9 f is at each vacuum opening 9 c, 9 d, through achannel 9 h, connected with an ejector 9 g such that a jet D ofcompressed air with high speed is formed in an ejector passage 9 k. Thisjet D of compressed air generates a vacuum in a vertical hole 9 m whichat the top communicates with each vacuum opening 9 c, 9 d, whereby avacuum, i.e. a negative pressure, is generated also in each vacuumopening 9 c, 9 d as well as in vacuum holes 9 e communicating therewith,in the conveyor belt 9 a. The compressed air leaves the ejector 9 gthrough a compressed-air outlet 9 n.

[0044] There may be a device generating a vacuum at the beginning of avacuum means 9 b, seen in the main transport direction A, while itgenerates less or no vacuum at the end of the vacuum means 9 b, suchthat a vacuum is generated in vacuum holes 20 in a conveyor belt 14running around the vacuum means 9 b when said vacuum holes 20 pass thebeginning of the vacuum means 9 b, but less vacuum or no vacuum isgenerated when said vacuum holes 20 pass the end of the vacuum means 9b.

[0045] Since the first vacuum opening 9 c has closed end portions 9 ca,9 cb while the second vacuum opening 9 d has one open end portion 9 db,the vacuum effect can be brought to be larger in the first vacuumopening 9 c than in the second vacuum opening 9 d. Since the open endportion 9 db of the second vacuum opening 9 d is situated at a rear end9 ba of the vacuum means 9 b, i.e. that end which—seen in the maintransport direction A—is situated where the sheets 2 leave the conveyorbelt 9 a, the vacuum effect will be less at the rear end portion 9 db ofthe vacuum opening 9 d than at its front end portion 9 da. Hereby, it isachieved that the vacuum effect is at its largest at the beginning ofthe vacuum opening 9 d, but diminish or decrease towards its end portion9 db, and hereby, the sheets 2 transported over the vacuum openings 9 c,9 d by the conveyor belts 9 a are affected by an ever decreasing vacuumuntil the leave the conveyor belts 9 a. This effect can be furtherimproved while the vertical hole 9 m of the vacuum generating device VAat the second vacuum opening 9 d is located closer to the first endportion 9 da of said second vacuum opening 9 d than to its second endportion 9 db. The vacuum means 9 b may of course have another number ofvacuum openings than two.

[0046] At the embodiment illustrated in FIG. 2, the stacking device 11includes a sheet conveyor 11 a for receiving laterally moved sheets 2from the device 10 for lateral movement, and for transferring saidsheets to a first or second stacking table 11 b, 11 c such that stacks2A, 2B of sheets according to FIG. 3 are formed thereon. The stackingdevice 11 further includes a first elevator device 11 d which canreceive one stacking table 11 b or 11 c at a time and lower itsuccessively while said stacks 2A, 2B of sheets are formed. The firstelevator device 11 d can lower the stacking table 11 b or 11 c to astack conveyor 11 e which is adapted to transport the stacks 2A, 2B awayfrom the respective stacking table 11 b, 11 c. The stack conveyor 11 eincludes a number of conveyor belts 11 f and each stacking table 11 b,11 c has elongated holes 11 g for said conveyors 11 f. The firstelevator device 11 d can lower each stacking table 11 b, 11 c so farrelative to the stack conveyor 11 e that its conveyor belts 11 f frombelow will project upwards through the holes 11 g in the respectivestacking table 11 b, 11 c. Hereby, stacks 2A, 2B lying on the respectivestacking table 11 b, 11 c will instead locate themselves on the conveyorbelts 11 f (see FIG. 14), which will feed them away from the stackingtable 11 b, 11 c.

[0047] A lower transfer device 11 h is provided for moving the stackingtables 11 b, 11 c from the first elevator device 11 d to a secondelevator device 11 k, which is adapted to receive said stacking tables.This may occur when the respective stacking table 11 b, 11 c has beenreleased from the stack conveyor 11 e, and may be carried through bysaid first elevator device 11 d raising the stacking table 11 b, 11 csomewhat until it goes free from the stack conveyor 11 e. The secondelevator device 11 k is provided to raise the respective stacking table11 b, 11 c from its cooperation with the lower transfer device 11 h inupwards direction to a ready position BL, in which it is located justbeneath the sheet conveyor 11 a (see FIG. 11). During this movement, thestacking table 11 b and 11 c respectively, has also been brought tocooperate with an upper transfer device 11 m. This is done by providingthe upper transfer device 11 m with at least one downwardly directeddriver 11 n, which will be inserted into a hole 11 p in the respectivestacking table 11 b, 11 c by raising said stacking table to its readyposition.

[0048] The upper transfer device 11 m is provided to move the respectivestacking table 11 b, 11 c with high speed in a direction in parallel orsubstantially in parallel with the direction in which the sheet conveyor11 a transports the sheets 2 (arrow R; FIG. 12) from the ready positionBL to a receiving position ML (FIG. 13). During this movement, therespective stacking table 11 b, 11 c divides or cuts the flow AS1 and/orAS2 of sheets between two sheets 2 such that the stacking on a stackingtable is interrupted and stacking commences on the stacking table whichhas been moved into said flow AS1 and/or AS2 of sheets.

[0049] During said movement of the respective stacking table 11 b, 11 cinto the flow AS1 and/or AS2 of sheets, the stacking table 11 b, 11 c inquestion will be brought to cooperate with the first elevator device 11d. When stacking commences on the stacking table which has been movedinto the flow AS1 and/or AS2 of sheets, this stacking table is loweredby the first elevator device 11 d, and is thereby moved out ofcooperation with the driver 11 n of the upper transfer device 11 m. Theupper transfer device 11 m may then be reset to receive a stacking table11 b which is raised to ready position BL by the second elevator device11 k.

[0050] In FIGS. 11-14, the operation of the stacking device 11 isillustrated in more detail. Thus, FIG. 11 illustrates stacking of sheets2 on the first stacking table 11 b, which is located in a receivingposition ML and which is gradually lowered. The second stacking table 11c is set in its ready position BL and cooperates with the upper transferdevice 11 m.

[0051] In FIG. 12 it is shown how the other, second, stacking table 11 cis moved in the direction of arrow R by the upper transfer device 11 m,whereby said second stacking table 11 c is moved or transferred inbetween two sheets 2 in the flow AS1 and/or AS2 thereof, which flow isthen divided such that stacking of sheets 2 on the first stacking table11 b is interrupted and stacking of sheets commences on the secondstacking table 11 c without having to interrupt the flow AS1 and/of AS2of sheets.

[0052] In FIG. 13 it is shown how the first stacking table 11 b islowered with finished stacks 2A, 2B and how stacking is carried throughon the second stacking table 11 c. The second stacking table 11 c hasbeen lowered out of engagement with the upper transfer device 11 m, i.e.it is situated beneath the driver 11 n.

[0053] In FIG. 14 it is shown how the first stacking table 11 b has beenlowered relative to the stack conveyor 11 e such that the stacks 2A, 2Bhave been placed from above on the conveyor belt 11 f of the stackconveyor 11 e for transport thereby of the stacks 2A, 2B away from thefirst stacking table 11 b. Additionally, the upper transfer device 11 mhas been reset such that it can be brought to cooperate with the firststacking table 11 b when said stacking table is raised to the readyposition BL.

[0054] In this way, both stacking tables 11 b, 11 c can be brought tointerrupt the flows AS1 and AS2 of sheets alternatingly, such that oneof the stacking tables 11 b, 11 c always is in receiving position ML forreceiving sheets 2, while the other stacking table 11 b, 11 c is in aready position BL for quick transfer or movement into a flow of sheets.

[0055] The elevator devices 11 d, 11 k and the transfer devices 11 h, 11m may include endless belts for movement of the stacking tables 11 b, 11c, but said devices may of course be designed in other ways. If theupper transfer device 11 m has a driver 11 n, said driver may be locatedon the endless belt of the transfer device 11 m.

[0056] There may of course be more than two stacking tables in thestacking device 11 if necessary.

[0057] In FIG. 10 it is illustrated that the transport device 9 cantransport or feed sheets 2 in at least two flows AS1 and AS2 of sheets.The sheets 2 in the flow AS1 thereof are transported to a first pair TB1of conveyor belts and the sheets 2 in the flow AS2 thereof to a secondpair TB2 of conveyor belts for lateral movement of the sheets in eachflow AS1, AS2 of sheets relative to each other, and thereby form twodifferent groups of stacks beside each other.

[0058] The conveyor belts 14 in each pair TB1, TB2 thereof are mountedsuch that an angle between each conveyor belt 14 and a centre line CLbetween said conveyor belts are the same or substantially the same. Thepairs TB1, TB2 of conveyor belts are located relative to each other suchthat their centre lines CL—seen in the main transport directionA—diverge. The angle δ between said centre line CL and the maintransport direction A is preferably larger than 2° and less than 30 °.

[0059] Since the pairs TB1, TB2 of conveyor belts are mounted with theircentre lines CL making an angle δ relative to each other, it is possibleto form two groups of stacks beside each other and if there are morethan two pairs of conveyor belts, more than two groups of stacks can beformed beside each other.

[0060] By operating both conveyor belts 14 in each pair TB1, TB2thereof, it is possible to form more such groups of stacks beside eachother, where each group of stacks contains several, relative each otherlaterally displaced stacks 2A, 2B. By operating only one conveyor belt14 in at least one pair TB1 and/or TB2 of conveyor belts, several groupsof stacks can be formed beside each other, where the sheets 2 are notlaterally displaced relative each other within the group of stacks.

[0061] The device described above may vary within the scope of theappended claims with regard to its operation and construction. Asexamples of not further described alternatives, it should be mentionedthat the vacuum generating device V and/or VA can generate a vacuum inother ways than with compressed air and with other devices than ejectors24 and 9 g respectively, and that the vacuum interrupting or vacuumwithdrawing device 31 can interrupt the presence of vacuum in other waysthan with compressed air and when interrupting or withdrawing a vacuum,this can be carried through in other ways than with compressed air.Also, each vacuum means 12, 13 and 9 b respectively, may be providedwith another number of vacuum openings 17, 18, 19 and 9 c, 9 drespectively, than the number shown in the drawings, and said vacuumopenings may preferably be elongated and situated in a row, in line witheach other. Furthermore, it should be mentioned that the device 10 forlateral movement can be located in another position in the plant 1 thanthe one shown, it may include another suitable number of conveyor belts14 than shown and it may include conveyor belts 14 which instead aremounted above a friction plate and which transport and move laterallythe sheets on said friction plate. It should finally be mentioned thatthe compressed-air generating devices 23 and 9 f respectively, may beone and the same device.

[0062] Also, in the plant 1 there may be more than one transport device9 and/or may said transport device or transport devices 9 be located inother places in the plant 1. Each transport device 9 may include six oranother suitable number of conveyor belts 9 a with associated vacuummeans 9 b.

1. Device for lateral movement of sheets (2) during transport thereof toa stacking device (11) such that the sheets (2) or stacks (2A, 2B) ofsheets (2) occupy laterally displaced positions relative to each otherin the stacking device (11), wherein a high-speed printer (6) isprovided for printing the sheets (2) or at least one continuous web (5)which is cut to sheets, wherein the device comprises at least one pairof conveyor belts (14) which are diverging relative to a main transportdirection (A) such that they can move sheets (2) laterally in differentlateral directions (B, C) relative to said main transport direction (A),and wherein a gripping and contact maintaining appliance is providedsuch that the conveyor belts (14) can grip or engage sheets (2) and holdthem in contact with said conveyor belts (14) for transport thereby,characterized in that said gripping and contact maintaining device is avacuum generating device (V) having vacuum means (12, 13) with vacuumopenings (17, 18, 19) located within vacuum holes (20) in the conveyorbelts (14), and provided to generate a vacuum in said vacuum openings(17, 18, 19) and vacuum holes (20) so that said conveyor belts (14) cangrip or engage and transport the sheets (2), and that a device fordetermining which conveyor belt (14) of the two vacuum means (12, 13)that shall transport the sheets (2), is a vacuum control device (30)which controls the vacuum generating device (V) to alternatingly eithergenerate a vacuum in at least one vacuum opening (17, 18, 19) in one ofthe vacuum means (12) or in at least one vacuum opening (17, 18, 19) inthe other vacuum means (13) such that one or more sheets (2) is/areengaged and transported or fed by one or the other conveyor belt (14) ofsaid vacuum means (12, 13).
 2. Device according to claim 1,characterized in that each vacuum means (12, 13) has at least two vacuumopenings (17, 18, 19), that the vacuum control device (30) is providedto control the vacuum generating device (V) to generate a vacuum in atleast a first one (17) of several vacuum openings (17, 18, 19) in atleast a first one (12) of said vacuum means (12, 13), and that thevacuum control device (30) is provided to control the vacuum generatingdevice (V) to not generate a vacuum at the same time or withdraw thevacuum at the same time in at least a first one (17) of several vacuumopenings (17, 18) in at least a second one (13) of said vacuum means(12, 13) and vice versa.
 3. Device according to claim 2, characterizedin that the vacuum control device (30) is provided to control the vacuumgenerating device (V) to generate a vacuum in at least a first one (17)of several vacuum openings (17, 18, 19) in the first vacuum means (12),that the vacuum control device (30) is provided to control the vacuumgenerating device (V) to not at the same time generate a vacuum orwithdraw the vacuum in at least a first one (17) of several vacuumopenings (17, 18, 19) in the second vacuum means (13), and that thevacuum control device (30) is provided to control the vacuum generatingdevice (V) to simultaneously generate a vacuum in at least a secondvacuum opening (18, 19) in the second vacuum means (13).
 4. Deviceaccording to claim 3, characterized in that the vacuum control device(30) is provided to control the vacuum generating device (V) to generatea vacuum in said first vacuum opening (17) in said first vacuum means(12), and not at the same time generate a vacuum or at the same timewithdraw the vacuum in at least one other (18, 19) of said vacuumopenings (17, 18, 19) in said first vacuum means (12).
 5. Deviceaccording to claim 3 or 4, characterized in that the vacuum controldevice (30) is provided to control the vacuum generating device (V) tonot at the same time generate a vacuum or interrupt the vacuum in saidfirst vacuum opening (17) in said second vacuum means (13) and at thesame time generate a vacuum in at least one other (18, 19) of saidvacuum openings (17, 18, 19) in the second vacuum means (13).
 6. Deviceaccording to any of claims 2-5, characterized in that the vacuum controldevice (30) is provided to control the vacuum generating device (V) togenerate a vacuum in all vacuum openings (17, 18 19) provided in thefirst vacuum means (12), and that the vacuum control device (30) isprovided to control the vacuum generating device (V) to simultaneouslynot generate or interrupt the vacuum in all vacuum openings (17, 18, 19)provided in the second vacuum means (13).
 7. Device according to any ofclaims 2-6, characterized in that the vacuum control device (30) isprovided to control the vacuum generating device (V) to, on one hand,generate a vacuum in a vacuum opening (17, 18 or 19) when the conveyorbelt (14) transports a sheet (2) thereto and front portions of the sheet(2) are situated outside said vacuum opening (17, 18, 19), and to, onthe other hand, interrupt or withdraw the vacuum in said vacuum opening(17, 18, 19) when said front portions of the sheet (2) have left thearea outside said vacuum opening (17, 18 or 19).
 8. Device according toany preceding claim, characterized in that two conveyor belts (14) arelocated so close to each other and the sheets (2) have such size thatthey during transport on one of the conveyor belts (14), at least duringa part of their transport along this conveyor belt (14), move above theother conveyor belt (14).
 9. Device according to any preceding claim,characterized in that the vacuum generating device (V) includes at leastone compressed-air generating device (23) and at least one ejector (24)at each vacuum means (12, 13), and that compressed air from thecompressed-air generating device (23) is supplied to the ejector (24)such that a jet (D) of compressed air therein generates a vacuum in thevacuum openings (17, 18, 19) of the vacuum means (12, 13) and in thevacuum holes (20) communicating therewith, in the conveyor belts (14).10. Device according to claim 9, characterized in that at least oneejector (9 g) is located in an elongated vacuum means (12 and/or 13)around which the conveyor belt (9 a) runs.
 11. Device according to claim9 or 10, characterized in that a vacuum interrupting or vacuumwithdrawing device (31) is provided to supply compressed air from thecompressed-air generating device (23) to the vacuum openings (17, 18 and19 respectively) in the vacuum means (12, 13) in order to interrupt orwithdraw the vacuum in said vacuum openings (17, 18, 19) and in thevacuum holes (20) communicating therewith, in the conveyor belts (14).12. Device according to any of claims 9-11, characterized in that thevacuum interrupting or vacuum withdrawing device (31) has valves (32)which either can be set in closed positions for guiding compressed airfrom the compressed-air generating device (23) to the ejectors (24), orin open positions for guiding compressed air to the vacuum openings (17,18, 19) in the vacuum means (12, 13).
 13. Device according to any ofclaims 9-12, characterized in that at least one vacuum interrupting orvacuum withdrawing device (31) is provided to not interrupt or withdrawthe vacuum in at least a first one (17) of several vacuum openings (17,18, 19) in a first vacuum means (12), while at least one vacuuminterrupting or vacuum withdrawing device (31) is provided tosimultaneously interrupt or withdraw the vacuum in at least a first one(17) of a plurality of vacuum openings (17, 18, 19) in a second vacuummeans (13).
 14. Device according to any of claims 9-13, characterized inthat at least one vacuum interrupting or vacuum withdrawing device (31)is provided to interrupt or withdraw the vacuum in at least one vacuumopening (17, 18 or 19) in a vacuum means (12 or 13), but not at the sametime interrupt or withdraw the vacuum in at least one other vacuumopening (17, 18 or 19) in the same vacuum means (12 or 13).
 15. Deviceaccording to any of claims 9-14, characterized in that thecompressed-air generating device (23) communicates with a plurality ofejectors (24) at a plurality of vacuum openings (17, 18, 19) in a vacuummeans (12, 13).
 16. Device according to any of claims 10-15,characterized in that the vacuum interrupting or vacuum withdrawingdevice (31) is provided to interrupt or withdraw the vacuum in a vacuumopening (19) when rear portions of a sheet (2) pass the area at saidvacuum opening and front portions of said sheet (2) are brought to leavethe conveyor belt (14).
 17. Device according to any preceding claim,wherein a transport device (9) is provided to transport sheets (2) in atleast two flows (AS1, AS2) thereof, wherein conveyor belts (14) in afirst pair (TB1) thereof are provided to laterally move sheets (2) inone flow (AS1) of sheets and conveyor belts (14) in a second pair (TB2)thereof are provided to laterally move sheets (2) in the other flow(AS2) of sheets, and wherein the conveyor belts (14) in each pair (TB1and TB2 respectively) thereof are mounted such that an angle betweeneach conveyor belt (14) and a centre line (CL) between the conveyorbelts is the same or substantially the same, characterized in that thepairs (TB1, TB2) of conveyor belts are located relative to each othersuch that their centre lines (CL), seen in the main transport direction(A), diverge for providing groups of stacks located beside each other.18. Device according to claim 17, characterized in that both conveyorbelts (14) in each pair (TB1 and TB2 respectively) thereof are operablein order to form, with each pair of conveyor belts, several groups ofstacks with, relative to each other, laterally displaced stacks (2A, 2B)of sheets (2).
 19. Device according to claim 18, characterized in thatonly one conveyor belt (14) in each pair (TB1 and TB2 respectively)thereof is operable in order to form, by means of each pair (TB1, TB2)of conveyor belts, one or more groups of stacks with, relative to eachother, not laterally displaced sheets within each group of stacks. 20.Device according to any preceding claim, wherein a device fortransporting sheets (2) is provided in a plant (1) in which a high-speedprinter (6) is included for printing said sheets (2) or at least onecontinuous web (5) which is cut into sheets (2), said transport device(9) being provided to transport the sheets (2) in at least one flow (AS1and/or AS2) thereof or at least one continuous web (5), wherein thetransport device (9) includes at least one vacuum means (9 b) with atleast one vacuum opening (9 c, 9 d) which communicates with vacuum holes(9 e) in at least one conveyor belt (9 a), and wherein a vacuumgenerating device (VA) is provided to generate a vacuum in the vacuumopening (9 c, 9 d) of the vacuum means (9 b) such that said conveyorbelt (9 a) can engage and transport the sheets (2), characterized inthat the vacuum generating device (VA) comprises a compressed-airgenerating device (9 f) from which compressed air is fed or supplied toan ejector (9 g) such that a jet (D) of compressed air therein generatesa vacuum in the vacuum opening (9 c, 9 d) in the vacuum means (9 b) andin the vacuum holes (9 e) in the conveyor belts (9 a).
 21. Device forlateral movement of sheets (2) during transport thereof to a stackingdevice (11) such that the sheets (2) or stacks (2A, 2B) thereof occupylaterally displaced positions relative to each other in the stackingdevice (11), wherein a high-speed printer (6) is provided for printingthe sheets (2) or at least one continuous web (5) which is cut to sheets(2), wherein the device comprises at least one pair of conveyor belts(14) which are diverging relative to a main transport direction (A) suchthat they can move sheets (2) laterally in different lateral directions(B, C) relative to said main transport direction (A), and wherein agripping and contact maintaining appliance is provided such that theconveyor belts (14) can grip or engage sheets (2) and hold them incontact with said conveyor belts (14) for transport thereby,characterized by a device which generates a vacuum at the beginning of avacuum means (9 b), seen in the main transport direction (A), while itgenerates less or no vacuum at the end of the vacuum means (9 b), suchthat a vacuum is generated in vacuum holes (20) in a conveyor belt (14)running around the vacuum means (9 b) when said vacuum holes (20) passthe beginning of the vacuum means (9 b), but less vacuum or no vacuum isgenerated when said vacuum holes (20) pass the end of the vacuum means(9 b).
 22. Device according to claim 21, characterized in that eachvacuum means (9 b) has at least one vacuum opening (9 d) with adecreasing vacuum effect—seen in the main transport direction (A)—suchthat the suction force on the sheets (2) or the continuous web (5)diminishes when said sheets or web are/is transported along the vacuumopening (9 d).
 23. Device according to claim 22, characterized in thateach vacuum means (9 b) has at least one vacuum opening (9 d) with aless vacuum effect—seen in the main transport direction (A) for thesheets (2) or the continuous web (5)—at a rear end (9 ba) of the vacuummeans (9 b) than at portions thereof located in front of said rear end(9 ba).
 24. Device according to claim 23, characterized in that saidvacuum opening (9 d) has a closed end portion (9 da) and an open endportion (9 db), whereby the open end portion (9 db) is located at therear end (9 ba) of the vacuum means (9 b).
 25. Device according to claim24, characterized in that the vacuum opening (9 d) has an end portion (9da) which—seen in the main transport direction (A) of the sheets (2) orthe continuous web (5)—is located in front of the open end portion (9db), and that a hole (9 m) through which the ejector (9 g) communicateswith the vacuum opening (9 d) is located closer to the firstmentionedend portion (9 da) than to the open end portion (9 db).
 26. Deviceaccording to any of claims 23-25, characterized in that the vacuum means(9 b) has at least two vacuum openings (9 c, 9 d) which are locatedafter each other, that a first vacuum opening (9 c) has two closed endportions (9 ca, 9 cb) and that a second vacuum opening (9 d) has aclosed end portion (9 da) and—seen in the main transport direction (A)for the sheets (2) or the continuous web (5)—an open end portion (9 db)located after said closed end portion.
 27. Device according to anypreceding claim, wherein a stacking device is provided for stackingsheets (2), wherein a high-speed printer (6) is provided for printingthe sheets (2) or at least one continuous web (5) which is cut to sheets(2), and wherein the stacking device (11) is provided to receive sheets(2) in at least one flow (AS1 and/or AS2) thereof to said stackingdevice (11) and to transfer said sheets (2) in the flow (AS1 and/or AS2)thereof to at least one first stacking table (11 b) in order to formthereon at least one stack (2A and/or 2B) of sheets (2), characterizedin that at least one second stacking table (11 c) is provided fordisplacement in between two sheets (2) in the flow (AS1 and/or AS2)thereof when sheets (2) therein are transferred to the first stackingtable (11 b) such that the second stacking table (11 c) divides or cutsthe flow (AS1 or AS2) of sheets between said two sheets (2) andinterrupts the formation of at least one stack (2A and/or 2B) of sheets(2) on the first stacking table (11 b) and permits formation of at leastone stack (2A and/or 2B) of sheets (2) on the second stacking table (11c) without interrupting or stopping the flow (AS1 and/or AS2) of sheets(2).
 28. Device according to claim 27, characterized in that the firststacking table (11 b) is provided for displacement in between two sheets(2) in the flow (AS1 and/or AS2) of sheets when this is transferred tothe second stacking table (11 c) such that the first stacking table (11b) divides or cuts the flow (AS1 or AS2) of sheets between said sheets(2) and interrupts the formation of at least one stack (2A and/or 2B) ofsheets (2) on the second stacking table (11 c) and permits formation ofat least one stack (2A and/or 2B) of sheets (2) on the first stackingtable (11 b) without interrupting or stopping the flow (AS1 and/or AS2)of sheets (2).
 29. Device according to claim 27 or 28, characterized inthat a transfer device (11 m) is provided to move or transfer one of thestacking tables (11 b, 11 c) from a ready position (BL) to a receivingposition (ML) in order to cut or divide during this movement the flow(AS1 and/or AS2) of sheets between two sheets (2) and interrupt theformation of at least one stack (2A and/or 2B) of sheets (2) on oneother stacking table (11 b, 11 c).
 30. Device according to claim 29,characterized in that the transfer device (11 m) has at least one driver(11 n) for moving the stacking tables (11 b, 11 c), that the stackingtables (11 b, 11 c) during movement upwards to the ready position (BL)are brought to cooperate with said driver (11 n), and that the stackingtables (11 b, 11 c) during movement downwards while stacks (2A and/or2B) of sheets (2) are formed thereon, are brought out of cooperationwith the driver (11 n).
 31. Device according to claim 30, characterizedin that the transfer device (11 m) includes at least one endless beltfor moving the stacking tables (11 b, 11 c), that the driver (11 n) islocated on the endless belt, and that each stacking table (11 b, 11 c)has at least one hole (11 p) for engagement by the driver (11 n). 32.Device according to claim 31, characterized in that each stacking table(11 b and 11 c respectively), when situated in its ready position (BL),is located under or beneath a sheet conveyor (11 a) which transports thesheets (2) to a stacking table (11 b and 11 c respectively) which issituated in receiving position (ML), and that each stacking table (11 b,11 c) is movable from the ready position (BL) to the receiving position(ML) in a direction in parallel or substantially in parallel with thedirection in which the sheet conveyor (11 a) transports the sheets (2).33. Device according to any of claims 28-32, characterized in that eachstacking table (11 b, 11 c) is lowerable to a stack conveyor (11 e)which is provided to transport stacks (2A and/or 2B) on the stackingtable away from said stacking table.
 34. Device according to claim 33,characterized in that each stacking table (11 b, 11 c) is lowerable tosuch position relative to the stack conveyor (11 e) that conveyor belts(11 f) forming part thereof can protrude up through holes (11 g) in therespective stacking table (11 b, 11 c), whereby stacks (2A, 2B) ofsheets (2) on the stacking table (11 b or 11 c) will lie on the conveyorbelts (11 f) for transport thereby away from the stacking table (11 b or11 c).